CastT

CastT is a cross-language runtime type casting framework designed to standardize value conversion between types across dynamic and statically typed languages. It provides a core casting engine and a meta-type registry that describe permissible conversions and their error behavior, enabling predictable and auditable casts.

Origin and development: CastT was introduced in 2021 by CastTech Labs as an extension to the CastCore project. It is released as open-source software under the MIT License and maintains adapters for popular runtimes such as JavaScript, Python, and Java.

Architecture: The framework comprises a lightweight core engine, a type registry, runtime adapters, and a policy module that defines casting rules with precedence, nullability, and failure handling. The type registry is extensible, allowing users to register domain-specific types and conversion paths.

Features: CastT supports explicit cast expressions, robust null handling, overflow and precision control, and customizable cast policies. It provides diagnostic messages for failed casts and supports result caching to improve performance in repeated conversions.

Usage: Developers declare cast rules for their types and apply CastT casts within their code or data pipelines. Typical workflows include validating input data, transforming payloads between languages, and enforcing schema boundaries at API edges.

Limitations and reception: Adoption is concentrated in projects that require cross-language data exchange or strict casting guarantees. Overhead from policy resolution and runtime checks is a consideration, though caching mitigates it. The project maintains active core contributors and welcomes community participation.

See also: type casting, type system, interoperability, runtime environment.